Heat exchanging apparatus



'Oci. 31, 1939. E. r. LINDEROTH HEAT EXCHANGING APPARATUS Filed Feb. 2,1937 5 Sheets-Sheet l Oct. 31, 1939. E. 1'. LINDEROTH HEAT EXCHANGINGAPPARATUS Filed Feb. 2, 1937 5 Sheets-Sheet 2 Oct. 31, 1939. E. T.LINDEROTH 2.178.481 1 HEAT EXCHA NGING APPARATUS Filed Feb. 2, 1937 5Sheets-Sheet 3 azing/922% @ck. 3Y1, 11%3Q. 41, UNDEROTH 2,178,481

HEAT EXCHANGINGHAPPARATUS Filed Feb. 2, 1937 5 Sheets-Sheet 4 0d. 31,1939- E; T. LINDROTH 2.178.481

HEAT EXCHANGING APPARATUS Filed Feb. 2, 1937 5 Sheets-Sheet 5 Z y dh/ardPatented @ct. M, 193% UbiiTEfi fiTATES mmdtli PATENT QFFIQE ApplicationFebruary 2, 193?, Serial No. 123,705 In Sweden February 111, I936 8Claims.

This invention relates to heat exchanging apparatus for utilizing theheat in warm exhaust gases, such as from steam boilers, furnaces, dryingplants, and the like.

The subject matter of the invention is par ticularly directed to aregenerative air preheater, although, the idea forming the basis of theinvention may be applied in utilizing the gas heat for another purpose,such as preheating water, in which case, however, the regenerative heattransmission principle must be abandoned.

According to the invention the heat transfer surface consists of wires,or similar elements, for example in the shape of one or several wiregauzes, which are spaced in such a way relatively to one another and tothe relative direction of motion between the flowing gas and the heatsurface that the gas current is divided into thin layers which areconsiderably thinner than the distance between the elements.

A very suitable embodiment, by which a considerable increase of the heattransmission output is obtained, is to dispose wire gauze in the shapeof a cylinder rotating at a peripheral speed which is considerablygreater than the radial speed at which the gas flows through the wiregauze.

In order to illustrate the output thus obtained reference is made to theknown fact that if a fine-meshed wire gauze is held above a flame theflame is not able to penetrate the wire gauze because the glowing gasmasses are quickly cooled to such a low temperature that the combustionceases. This output is extraordinary since in comparison with commonheat surfaces it means an exceptionally high specific heat transmissionoutput.

For example, the gases in a steam boiler have to flow a long way beforea corresponding cool- 40 ing has been effected. The cooling in the wiregauze takes place in a distance less than a millimetre, viewed in thedirectionof flow. The high heat transmission of the wire gauze isparticularly due to the fact that the gas is divided into a number ofthin layers with intermediate cooling surfaces whereby the gas layersare quickly cooled.

The output obtained in the indicated embodiment by the rotation of thewire gauze cylinder is illustrated diagrammatically in Figure 1 of theaccompanying drawings, in which:

I indicates wires disposed axially in the wire gauze cylinder. In thetriangle below Figure 1 Wu represents the peripheral speed of the wiregauze cylinder, and W1 the radial flow speed at which the gas flowsthrough the wire gauze. R then indicates the relative movement betweenthe gas and the wires i. It is just the same as if the gas had movedagainst the wire gauze in the direction R. The thickness of the gaslayers a, 5 which flow through the spaces between the wires I, nowbecomes only a fraction of the distance 6 between the wires. Thus, inorder to obtain a thorough heating and cooling respectively of the wholegas layer the heat may be conducted a considerably shorter distance thanif the gas flowed through the wire gauze perpendicularly to the surfaceof the same. Thus, the described embodiment involves a considerablyincreased specific heat transmission output. 15

Under these circumstances the axial wires in the gauze are the mostactive ones although the turbulence caused by the rotation of the wiregauze increases the heat transmission output also in the tangentialwires. A suitable arrangement according to the invention is to disposethe wire gauze in such a way in the cylinder that the wires will belocated at an angle of 45 to the axis. The heat exchange surface mayalso be composed of axial wires only, the said wires being arranged soas to form a cylinder. Instead of wires I one may also disposecorresponding elements in the shape of sheet metal strips withoutabandoning the basic idea of the invention.

An example is shown diagrammatically in Figure 2 in which the strips areindicated by I just as the wires in Figure 1. The other referencenumerals also of Figure '2 relate to the same details as those ofFigure 1. In the device according to Figure 2 the gas layers a arecooled and heated respectively mainly from one side only. By way ofrecompense the elements I have here greater dimensions in the directionof flow of the gas than the wires in Figure 1. However, the most activepart of the heat exchanger surface is always the one located nearest tothe border of inflow. According to the present invention the elementscomposing the heat transfer surface should therefore be very short inthe direction of flow of the gas, and preferably shorter than thedistance between the elements. This also makes it possible to obtain anefiective scavenging from soot, since according to the invention the gasflows through the heat exchange surface, i. e., the intermediate spacesformed between the elements in the heat' surface, are meant to haveexceptionally small sections.

The heat transmission coefficients obtained according to the inventionare so high that a slight soot layer on the heat surface would besuflicient 55 to make it impossible to obtain coefficients. Therefore,the invention also includes such a sweeping device that the heat surfacemay be held completely free from soot.

Preferably, the rotating heat exchange surface is disposed in a knownway in a fan casing wherebyfthe heat exchanging apparatus also serves asa an.

Some embodiments of the invention are illustrated in the accompanyingdrawings.

Figure 3 is a cross section and Figure 4 a longitudinal section throughan apparatus according to one embodiment relating to a regenerative airpreheater.

Figure 5 is an elevational view of a modified cleaning device whereinsome of the parts are shown in section.

Figure 6 is a sectional view of a mechanical sweeping device.

Figure 7 is a side view of the apparatus shown in Figure 6.

Figure 8 is a cross-sectional view of another form of the heat exchangeapparatus.

Figure 9 is an elevational view illustrating means for rotatablysupporting a wire gauze heat transfer member. I

Figure 10 is a sectional view of another form of heat transferapparatus.

Figure 11 is an end view of apparatus for recovering heat inventilation.

Figure 12 is a sectional View of the apparatus shown in Figure 11.

Figure 13 is a cross sectional view showing another form of heatconducting element; and

Figure 14 is a longitudinal section of the apparatus shown in Figure 13.

The regenerator consists of a cylindrical shaped wire gauze I, supportedat one end by a discshaped wheel 2 which is rotatably mounted on a shaft3. At the opposite end of the wire gauze cylinder the wire gauze isstrengthened by an external ring 4. The interior of the wire gauzecylinder is by means of a stationary baffle or partition 5 divided intotwo chambers, one for the gas A and one for the air B. The hot gasesenter the chamber A through the connection piece 6, .pass through therotating wire gauze cylinder l, and are thrown out from the same intothe lower spiral casing I surrounding the wire gauze cylinder on itsunderside. The spiral casing I merges into an upward directed diifuser 8in which the kinetic energy of the gas is converted into pressureenergy.

The air is sucked in at 9, passes the chamber 13, flows through the wiregauze cylinder l, and is thrown into the upper spiral casing l0 and thedownward directed diffuser H in which the kinetic energy of the air isconverted into pressure energy. Consequently, the apparatus is a gas fanas well as an air fan. Simultaneously it preheats the air and cools thegas. The heat transfer takes place through the wire gauze which absorbsheat from passing gas and gives off heat to the air passingtherethrough.

Thus, due to the draft in the chimney to which the gas is conducted fromthe diffuser 8, and due to the flow resistance in grate and furnace andsteam boiler respectively and in gas and air canals connected betweenthe diffuser H and the connection piece 6 there is always a lowerpressure in the chamber A and the spiral casing 1 than in the chamber Band the casing l0. Consequently, no leakage of smoke gases to the aircan take place, only a flow of air to the gas. However, this leakage ofair becomes insignificant due gauze cylinder.

to the small radial thickness of the regenerator. By a suitablepositioning of the stationary partition 5 the air and gas currents maybe so guided that a minimum of mixing is obtained under the pressureconditions considered to be normal for the preheater.

A very important detail in the construction of the air preheater is thecleaning device. This said device consists of a steam distributingchamber I2 disposed outside the casing I0, steam being supplied to thesaid chamber through the tube l3. From the chamber I2 the steam flowsout through a narrow slit I4 located quite close to the wire gauzecylinder 1 and extending along its whole width. Thus, the steam isprojected radially through the wire gauze. The inside of the steamchamber is stiffened by a number of stays I5.

If desired, also a similar steam blower "5 may be disposed on the insideof the wire gauze cylinder.

According to the invention it is intended to use very fine-meshed wiregauze to obtain a high heat transmission output. If no particular stepswere taken, stray cinder, half-burnt chips and other coarse particlesaccompanying the gas would be separated and collected on the inside ofthe wire To preclude this, there is provided a slit tube I1 inside thewire cylinder, the tube l'l catching the steam projected from the outersteam chamber l2. One end of the tube is closed and the other end isconnected to the diffuser 8. Thus, the particles, which are carried bythe wire gauze cylinder, will be blown into this tube and conveyed tothe chimney with the cooled gases.

The current from the steam blower may also be conveyed into the heatedair, unburnt particles being returned to the furnace and combusted.

If in such a case a very dense gauze is used the apparatus acts toreduce smoke since it then works as a self-cleaning filter for the smokegases.

An air preheater according to the present invention has to be swept veryoften if the intended high heat transmission output shall be maintained.The use of the preheater in practice requires a fully automaticoperation of the sweeping device.

An embodiment of a device for the automatic supply of steam to thesweeping is shown in Figure 4. A conical valve I8 is adapted to shut offthe steam supply to the steam blowers I2 and IS. The valve I8 isoperated by a piston IS in a cylinder 20. The area of the piston islarger than that of the valve cone. The steam is supplied beneath thepiston through a thin tube 2| which communicates with the steam pressuresupply in front of the valve 18. The supply of steam to the underside ofthe piston is choked by a valve 22 or a stationary choking member sothat the pressure beneath the piston rises slowly. When this pressurehas risen to such a value that the force exerted by the piston 19overweighs the pressure upon the conical valve l8 the latter is opened.As the friction is smaller in motion than at rest and as the pressureupon the valve I8 is somewhat reduced at the very instant when it leavesthe seat, the valve will open rather quickly if the movable parts have asmall mass, Consequently, the steam willbe discharged as a shot throughthe exhaust openings. When the piston has risen a certain distance itcloses an opening 23 in the upper part of the cylinder 20,

whereby the air above the piston i9 is compressed and moderates theupward motion of the piston. When the piston has passed the opening 23,the steam pressure is let out from the underside of the pistonwhereafter the piston begins to move downwards. For moderating thedownward motion of the piston there is preferably disposed a chokingmember 24 for the steam from the outlet opening 23.

Another embodiment of a cleaning device is shown in Figure 5 whichrelates to a continuously operating sweeping apparatus. Two small steamnozzles 25 are disposed one on each side of the wire gauze I. Steam orcompressed air is supplied through a flexible hose 26 and a movablydisposed branch tube 2'], 28. If the regenerator is cylindricalaccording to the above described embodiment the branch tube is providedwith two axially positioned branches, one on the outer side of theregenerator and one on the inner side of the same. The outer branch 2?,which lies in the air or gas current from the regenerator, haspreferably a streamline-shaped profile in order not to impede the gas orair current. The branch tube 21, 28 is given a slow reciprocate motionin the axial direction by a suitable transmission, for example arotatably mounted screw spindle 23 provided with two helically cutgrooves, one of the grooves being right-handed and the otherleft-handed. At the ends of the spindle the helical grooves merge in aknown way into one another so that a pin 30 engaging in the helicalgroove receives a reciprocate motion by the rotation of the screwspindle. The reciprocate motion of the pin 33 is transmitted to thebranch tube 21, 28 to which the pin is pivotally connected so that aflat part of the pin extending into the helical groove mayadjust itselffreely according to the pitch of the helical groove. The screw spindleis slowly rotated by a suitable transmission from the rotatingregenerator.

Figures 6 and 7 show a mechanical sweeping device by which theregenerator screen I may be kept clean from soot without consuming steamor compressed air for this purpose. The device consists of two round,rotatably disposed brushes 3i and 32 mounted on a fork-shaped frame 33which is so arranged that one brush moves on each side of the wire gauzeI. The frame 33 is given a reciprocate motion in a manner similar tothat described in connection with the steam sweeping apparatus accordingto Figure 5. The leg of the frame 33 located in the air or gas currentfrom the regenerator is preferably streamline-shaped. The brush of thesame is likewise provided with a streamline-shaped casing 34. Thebrushes 3! and 32, roll against the regenerator and are thereby rotated.The brushes will sweep over the whole surface of the regenerator due tothe reciprocate motion and keep the same clean. The brushes may also bemade in the shape of rolls extending over the whole width of theregenerator, thus making the reciprocate motion unnecessary. The brushesshould in this case be arranged in such a position as not to disturb thegas or air current. An'example of such a construction will behereinafter described.

If a greater cooling of the gas and a higher air preheating respectivelyare desired than can be obtained by an air preheater according toFigures 3 to 4 one may dispose two or several layers of gauze in theregenerator, at the same time applying the counter-current principle.

are in the lower poriton of the same disposed stationary guide rails 35which catch the gas current and convert its kinetic energy into pressureenergy. The gas is collected in the chamber A beneath the stationaryscreen 5 and is conducted to the chimney. The air is sucked in throughthe chamber B, passes the regenerator radially from the inside outwards,and is thrown through the helical worm casing ill to the diffuser H. Inorder to prevent overflow of gas to the air, where the regenerator movesin the direction from the gas chamber A to the air chamber B, a passageway 36 is provided for the gas-mixed air separated from the regenerator.The gas air mixture is returned to the gas inlet side and is here guidedthrough the regenerator towards the guide rails 35. If desired, the gasair mixture is conducted past the regenerator into the cooled gas. Thebottom of the passageway 36 merges into a chamber 3! in which soot andstray cinder are collected. The chamber 31 is emptied through the door'28. i2 and it are steam blowers for efiecting the cleaning of the heatexchange cylinder.

Due to the fact that the regenerator according to Figure 8 has two ormore layers of gauze and is passed in counter-current it is possible tocool the gas to a lower temperature than the heated air because theinner wire gauze, through which the colder gas and the colder air pass,assumes a lower temperature than the outer wire gauze through which hotgas and preheated air pass.

Under some conditions, it may be desired to dispense with a supportingconstruction within and around the regenerator. This is possible insmall and moderately large regenerators by arranging the inner wiregauze with the wires diagonally at an angle of 45 to the wires of theouter gauze. If, moreover. the wire gauzes are fixed to the wheel 2 andthe ring 4 (see Figure 4) and the gauze layers are mutually supported orjoined at several p aces a rather rigid construction is obtained.However, if fine-meshed gauze formed of small diameter wire is to beemployed large wheels cannot be used without special supports. In such acase the following construction is suggested:

In Figure 9 the reference numeral 4 indicates a ring which stiifens oneend of the wire gauze cylinder (compare Figure 4). 39 is thecorresponding ring in the cas ng. which surrounds the ring 4. Throughtwo tubes 40 and two bores 4| in the ring 39 steam under pressure (orcompressed air) is admitted to the space between the ring 4 and the ring39. The ring 4 then floatsin the ring 39 and may be turned without therearising any frictional resistance. In order to limit the steamconsumption a small choking nozzle 42 is inserted in each core.Moreover, the play between the rings should not be greater than what isnecessary with respect to the heat expansion. Further, the ring 39- hasan eccentric recess in its lower part between the two bores. Thus, ifthe ring 4 sinks against the ring 39 contact will first take placeadjacent the bores 4|. In order that the contact surface shall have acertain size and ofier a sufiicient pressure surface to the steam it ispreferable to allow the ring 4 to wear itself into the ring 39 adjacentthe two bores by means of grinding paste. No third supporting point (atthe top) is necessary for the ring 4 if the latter is sufficiently heavyin relation to the wire gauze so that it is not raised by. thevibrations of the gauze.

An embodiment of the invention relating to a directly fired hot airgenerator for drying, or for heating is shown in Figure 10.

For such a purpose the gas quantity to be cooled becomes only to of theair quantity to be heated if the apparatus is directly fired. The gas isvery hot, viz. 1.200 to 1.500 C. At the same time the preheated airshould be free from smoke gases and soot all of which necessitates aparticular construction. For this purpose the air preheater of thecountercurrent type is selected. However, only a single layer of wiregauze is necessary since in view of the great quantity of coo.- ing airthe wire gauze assumes a low temperature so that the gas is effectivelycooled. The countercurrent principle is chosen in this case only inorder that by the centrifugal force soot and stray cinder shall bethrown out from the regenerator through which the gas is led from theoutside inwards.

The air preheater is located above a furnace 43 in which fuel iscombusted with a large excess of air. The furnace is made so high andthe gas passage so long that the gases will have time to combustcompletely prior to their being led off at 6 and projected through theregenerator I. No considerable radiation from the fire takes place sincethe same is surrounded by insulating masonry on all sides. Thus, thegases are not cooled until they flow through the regenerator, andconsequently a high combustion efficiency may be expected. Only a smallpart of the regenerator is contacted by the smoke gases which are caughtby the guide rails 35, collected in the chamber A and led off to thechimney. The largest part of the regenerator is cooled by cool air whichis admitted through the chamber B and thrown out by the rotatingregenerator into the spiral casing l and the diffuser I I. Behind thegas-contacted part of the regenerator, viewed in the direction ofrotation, there is a space for a sweeping device which in this casepreferably should be made in the shape of two cylindric rotating brushes3| and 32 extending over the whole width of the wire gauze. Between thesweeping device and the air chamber B within the regenerator a chamber Cis provided for air which is to carry away soot and ashes removed by thebrushes from the regenerator. The transport air is caught by a smalldiffuser Ila and is admitted as combustion air into the furnace. Ifdesired, blowing away of stuff from the regenerator may be facilitatedby compressed air which is admitted through the chamber D and flowscontinuously through a slit l6 extending over the whole width of theregenerator. If compressed air as well as brushes are used the air neednot have so high a pressure but it may be produced plentifully in asimple way by a fan (not shown in the drawings). In order that hotcombustion gases from the furnace shall not leak into the chamber aroundthe brush 32 the chamber may be supplied with overpressure by connectingit with the just mentioned fan for scavenging air. In this constructionthe penetration of smoke gases into the heated fresh air is impossible.

Finally, Figures 11 and 12 show an embodiment of the invention for heatrecovery in ventila-.

tion. The regenerator here consists of radially extending wires 44clamped between two disc wheels 45, 46, carried by the shaft of anelectric motor 47. The device is supported by a cylindrical frame 48inserted in an outer wall 49 of the room to be aired. Fresh air issucked in by the stationary guide vanes 50 against which the air isthrown by the regenerator during rotation of the latter. The guide vanesmust be so shaped that they catch the air current from the regeneratorand direct it towards the interior of the room to be aired. The vanes 50cover-the lower half of the inside of the regenerator. On the outer sideof the regenerator there is in the same way disposed a vane rim whichdirects an air current outwards to the free air outside the wall. Thisair is cooled when passing through the regenerator, and the heat isconveyed over to the fresh air which flows in counter-current throughthe apparatus.

By such an apparatus it will be possible to obtain an ample ventilationalso at cold atmosphere without necessarily entailing any great lossesof heat.

In all of the above described apparatus air has been used as coolingmedium.- However, without departing from the basic idea of the inventionthe construction may be modified so that also liquids, such as water,may be heated by means of the heat of the exhaust gases. The problem insuch a heating has always been the heat transmitting output on the gasside, which output, at least within the ranges of temperature where theradiation is minimal, is rather bad in view of the low thermalconductivity of the gases. One has therefore usually'enlarged thesurface of the water tubes on the gas side (wrought-iron ribbed pipes).According to the present invention this surface enlargement consists ofwire gauze or the like, and at the same time in the manner describedabove the good heat transmitting output of the wire gauze is furtherincreased by causing the heat surface to rotate. An embodiment of suchan apparatus is shown in Figures 13 and 14.

The water is heated in a number of thin tubes 52 mounted on the wheel 2in such a way that they form a cylindric rim. Within this rim of tubes awire gauze l is disposed and soldered to all of the tubes along thewhole length of the tubes so that a good heat conducting contact arisesbetween the wire gauze and the tubes. The wire gauze is preferably soplaced that the wires lie at an angle of 45 to the tubes, in order thatall of the wires shall be soldered to the tubes.

For the circulation of the water through the tubes 52 the followingsteps are taken. One end of the tubes is connected to a hollow ring 4.At the opposite end the tubes are connected to the Wheel 2 andcommunicate here with an annular canal in the wheel. This canal is bymeans of two walls (not shown in the drawings) divided into twosemicircular parts 53 and 54. The water is admitted to one canal 53 by acanal 55 in the shaft 3 and by a radial extending canal 56 in the wheel2. From the canal 53 the water flows through half the number of tubes tothe ring 4 and from the said ring through the other tubes to the annularcanal 54. From here the water flows through the radial extending canal51 to a canal 58 in the shaft 3. For admitting the water to, and leadingthe same off from the rotating shaft 3 a casing 59 is disposed aroundthe shaft, the said casing being provided with two annular canals 60 and6|, which are connected to the inlet and outlet tubes by means of pipesockets 62. and 63. The annular canal 60 communicates with the canal 55in the shaft and the annular canal Bl with the canal 58. The two annularcanals t0 and El are tightened against the shaft by packing bushes.

The gas to be cooled is admitted at 6, is projected through the wiregauze l to which the gas delivers its heat, and is thrown into thespiral casing l to the difiuser 8. Thus, also this apparatus acts as afan at the same time as a gas cooler. The sweeping device l2, i5 and i'l is of the same construction as described in connection with Figures 3and 4.

If desired, the heat surface may be increased by a further layer orlayers of wire gauze around the tube rim 52. In order that the passagethrough which the heat is to be conducted through the thin wires in thegauze, shall be as short as possible the tubes 52 should be made verythin so that they may be placed at an insignificant distance from oneanother. The apparatus may preferably be carried out in such a way thatthe gas flows through the wire gauze from the outside inwards, the fanaction being obtained by a stationary vane rim located inside the wheel,as hereinabove described.

Having now described my invention, what I claim as new and desire tosecure by Letters Paten is:

1. Heat exchange apparatus for cooling and heating gases passingtherethrough comprising in combination, a rotatable regenerator whichconsists of at least one substantially cylindrical shaped wire screenproviding an apertured heat exchange member, means for projecting asupply of heated gas through the apertures of the heat exchange member,means circumferentially displaced from the first means for projecting anunheated gaseous medium through the apertures of said heat exchangemember, the wires of said screen being circumferentially spaced withrespect to each other and the transverse dimensions of each of saidwires in a direction radially of the heat exchange member being lessthan the circumferential spaces between the wires whereby the gases inpassing through the screen are divided into layers by the rotation ofthe heat exchange member which layers are considerably thinner than thecircumferential dimensions of said spaces.

2. Heat exchange apparatus for cooling and heating gases passingtherethrough comprising in combination, a rotatable regenerator whichconsists of at least one substantially cylindrical shaped wire screenproviding an apertured heat exchange member, means for projecting asupply of heated gas radially through the apertures of the heat exchangemember, means circumferentially displaced from the first means forprojecting an unheated gaseous medium radially through the apertures ofsaid heat exchange member, the wires of said screen beingcircumferentially shaped with respect to each other and the sectionaldimensions of each of said wires in a direction radially of the heatexchange member being less than the circumferential spaces between thewires whereby the gases in passing through the screen are divided intolayers by the rotation of the heat exchange member without completelyfilling the apertures thereof which layers are considerably thinner thanthe circumferential dimensions of said spaces.

3. Heat exchange apparatus for cooling and heating gases passingtherethrough comprising in combination, a rotatable regenerator whichconsists of at least one substantially cylindrical shaped wire screenproviding an apertured heat exchange member, means for projecting asupply of heated gas through the apertures of the heat exchange member,means circumferentially displaced from the first means for projecting anun heated gaseous medium through the apertures of said heat exchangemember, the wires of said screen being circumferentially spaced withrespect to each other and the transverse dimensions of each of saidwires in a direction radially of the heat exchange member being lessthan the circumferential spaces between the wires whereby the gases inpassing through the screen are divided into layers by the rotation ofthe heat exchange member which layers are considerably thinner than thecircumferential dimensions of said spaces, and said heat exchange memberbeing adapted to be rotated at-a peripheral speed which is manifoldlygreater than the speed at which the gases fiow through the screen.

4. Heat exchange apparatus according to claim 1 in which the heatexchange cylinder is supported at one end by a ring which is rotatablydisposed in an outer casing, said casing having openings in the lowerpart thereof into which a gaseous pressure is supplied for causing saidring to flow in said casing during relative rotation therebetween.

5. In heat exchange apparatus for cooling and heating gases passingtherethrough in combination of, a rotatable regenerator which consistsof at least one substantially cylindrical shaped wire screen providingan apertured heat exchange member, means for projecting a supply ofheated gas through the apertures of the heat exchange member, and meanscircumferentially displaced with respect to the first mentioned meansfor projecting an unheated gaseous medium through the apertures of theheat exchange member and the radial dimensions of the wires of thescreen being less than the circumferential dimensions of the apertures.

6. Heat exchange apparatus for cooling and heating gases passingtherethrough comprising in combination, an annular regenerator having adry surface mounted for rotation at relatively high speeds, saidregenerator including axially extending wires, said wires beingcircumferentially spaced with respect to each other and the transversedimension of each wire in a direction radially of the regenerator beingless than the circumferential spaces between the wires, means forprojecting a supply of heated gas radially against said wires andthrough the spaces between the wires, and means circumferentiallydisplaced from the first means for projecting an unheated gaseous mediumradially against said wires and through the spaces therebetween.

7. Heat exchange apparatus for cooling and heating gases passingtherethrough comprising in combination, an annular regenerator having adry surface mounted for rotation at relatively high speeds, saidregenerator including two layers of axially extending wires, the Wiresof said layers being circumferentially spaced with respect to each otherand the transverse dimension of each wire in a direction radially of theregenerator being less than the circumferential spaces between thewires, means for projecting a supply of heated gas radially against saidwires and through the spaces between the wires, and meanscircumferentially displaced from thefirst means for projecting anunheated gaseous medium radially against said wires and through thespaces therebetween.

through the spaces between the wires, and means circumferentiallydisplaced with respect to the first means for projecting an unheatedgaseous medium against said wires and through the spaces therehetween.

ERIK TORVALD LINDEROTH.

